1. Field of the Invention
This invention generally relates to vacuum cleaners, and more specifically to a belt disengaging device for an upright vacuum cleaner.
2. Description of the Related Art
Upright vacuum cleaners with rotating agitators are often provided with a device for stopping agitator motion by disengaging the agitator belt drive. Such belt disengaging devices physically disengages the agitator drive belt from the motor shaft but the vacuum motor continues to run. This process is useful when the vacuum cleaner is used for cleaning uncarpeted or bare floors, including hardwood, linoleum, tile, and tatami floors. Otherwise, the rotating agitator can generate air currents that push lightweight dust and debris away from the agitator so that they are not drawn through the suction nozzle and collected. A rotating agitator can also damage certain bare floors. It is also often desirable to disengage the agitator belt drive when the vacuum cleaner is left stationary and used for above-the-floor cleaning, as even more robust floor coverings might be damaged by the rotating agitator.
One general type of belt disengager is a “belt shifter”, where the agitator drive belt is shifted laterally from a driven pulley to an idler pulley. Both pulleys are usually on the end of the agitator brush roll. The agitator drive belt continues to run on the idler pulley, but does not engage the brush roll. Examples of belt shifters are disclosed in U.S. Pat. No. 2,682,680 to Trimble, U.S. Pat. No. 4,446,594 to Watanabe et al., and U.S. Pat. No. 5,839,160 to Wang et al., which are incorporated herein by reference in their entirety.
Another general type of belt disengager is a “belt tightener”. In these types of agitator drive belt systems, the drive belt is slack around an agitator drive pulley and a motor driven pulley, and thus the agitator will not rotate. To engage the belt, a belt tightener such as a pulley or a wheel is brought against the belt to take up the slack in the belt, thereby causing the agitator to rotate. Examples of belt tighteners are disclosed in U.S. Pat. No. 2,601,698 to Humphrey and U.S. Pat. No. 6,374,453 to Kim, which are incorporated herein by reference in their entirety.
A third general type of brush belt disengager is a “belt lifter”, wherein a member engages the belt to lift it away from a driven pulley or other driven member connected to the drive shaft of a motor. Examples of belt lifters are disclosed in U.S. Pat. No. 2,094,138 to White, U.S. Pat. No. 2,322,223 to Coss, U.S. Pat. No. 6,067,689 to Roney et al., and U.S. Pat. No. 6,098,243 to Kim, which are incorporated herein by reference in their entirety.